The Potential Public Health Relevance of Social Isolation and Loneliness: Prevalence, Epidemiology, and Risk Factors

Abstract

This article is a revised and updated version of testimony presented to the U.S. Senate Aging Committee on April 27, 2017. Our social relationships are widely considered crucial to emotional well-being; however, the possibility that social connection may be a biological need, vital to physical well-being and even survival, is commonly unrecognized. Still, extreme examples clearly illustrate infants in custodial care who lack human contact fail to thrive and often die (UNICEF, 1997), and social isolation is so distressing that solitary confinement has been used as a form of punishment and even torture. Yet an increasing portion of the U.S. population now experiences isolation regularly. News headlines from many nations, including the United States, Germany, Australia, and the United Kingdom, suggest that we are facing a loneliness epidemic (http://www.campaigntoendloneliness.org/loneliness-research, http://www.spiegel.de/international/germany/germany-faces-epidemic-of-lonely-and-isolated-seniors-a-876635.html, https://startsat60.com/health/new-survey-reveals-australias-loneliness-epidemic, http://www.huffingtonpost.com.au/tania-de-jong/loneliness-is-the-global-epidemic-of-our-times), leading to the important question of whether there is evidence to support such a claim and, if so, whether we are facing a public health crisis. Recently my work has systematically examined and summarized the available evidence supporting the public health prioritization of social connections (Holt-Lunstad, Robles, & Sbarra, 2017). Here I will summarize data on prevalence rates, epidemiological evidence of risk, and potential risk factors. According to one estimate, more than eight million older adults are affected by isolation (AARP, n.d.). However, this prevalence estimate is likely a conservative estimate given it is restricted to a specific age range and a narrow definition of social disconnection. Social isolation and loneliness are distinct experiences, but both are characterized by a lack of social connection. When we consider social connection more broadly, as a multi-dimensional construct (Holt-Lunstad et al., 2017)—including the extent to which relationships are present in our lives (e.g., structural aspects of relationships), the extent others can be relied upon (e.g., functional aspects of relationships), and our satisfaction with them (e.g., quality of relationships)—the prevalence of U.S. adults lacking social connection may be much larger. A precise estimate of the prevalence of adults in the United States that lack social connection is difficult, given that assessments are not currently systematically and routinely collected. However, some demographic characteristics that are indicators of social disconnection are routinely collected as part of census data. These data show that over a quarter of the U.S. population, and 28% of older adults, live alone (Vespa et al., 2013). More than half the U.S. adult population is unmarried, of which 20% have never married (Vespa et al., 2013). Further, approximately 40% of first marriages and 70% of remarriages end in divorce (United States Census Bureau, 2011). While such demographics are relatively crude indicators of social disconnection (e.g., someone who is single or lives alone may still have a wide social network) they are nonetheless robust predictors of health outcomes and thus should still be taken seriously. Data collected from nationally representative samples provide additional estimates of social disconnection that go beyond demographics. For example, more than one third of adults over age 45 report being lonely (Wilson & Moulton, 2010), equating to over 42 million older adults who experience chronic loneliness. Even among those who are married, over 30% of relationships are severely discordant (Whisman, Beach, & Snyder, 2008). Further, the majority of American adults do not participate in any kind of social group (Pew Research Center, 2009). Less than half of adults participate in a local religious group, and less than a quarter of adults participate in a social club, community group, sports league, or other local group (Pew Research Center, 2009). Taken together, these data suggest that a significant portion of the population, and older adults in particular, may be socially isolated/disconnected. Is there evidence that social isolation, loneliness, and relationship distress are increasing? In other words, are we becoming more socially disconnected? To address this question, we can look to these different sources of data to determine whether isolation (or social disconnection) is increasing to determine the degree of urgency of addressing this issue. For example, the average household size has decreased and there has been a 10% increase in those living alone (United States Census Bureau, 2011). The number of single occupancy households worldwide is now greater than ever in recorded history (Euromonitor International, 2014). Further demographic trends show reduct